IWSS/NCAP programme of work at Uisce Éireann sites

The scope

Inlet Works Storm Sludge Management (IWSS) and National Certificate of Authorisation (NCAP) programme is a large-scale complex project involving a multidisciplinary team across design, engineering and construction. The multi-site, multi-phase programme of works currently involves upgrades to 32 existing wastewater treatment plants (WwTP), with more expected to be added. The upgrade programme aims to improve compliance capacity, operational efficiencies, increase capacity and prolong the operational life of existing Uisce Éireann WwTP assets. 

The scope of works at each IWSS site typically comprises building new or upgrading existing inlet works, storm tanks, sludge tanks, sludge drying reed beds, pump stations with all ancillary civil, mechanical and electrical works. At NCAP sites, it typically involves construction and/or upgrade of every element of the WwTPs. 

The work

The project got underway in Q2 2021. Phase 1 consists of a detailed site survey, detailed design and TOTEX costings of the upgrade needed to bring the WwTP into compliance at proposed design PE. This detailed design goes through workshops 2 and 4 with all stakeholders and is then brought through a comprehensive HAZOP/ALM process. Conway Engineering manages this entire process. 

Once the HAZOP/ALM process is concluded, the detailed design phase is finalised and the project moves to the planning stage, where we work closely with the employer’s representative. Once planning is granted, Conway’s team project manages the construction phase including collaborative interaction with all relevant stakeholders. We build 3D models of each site, with extensive detail so that all stakeholders understand the proposals and are on board with upgrade works prior to completing Phase 1 of the programme. This detailed knowledge sharing ensures that when a site moves to Phase 2, construction can start without delay. 

We bring our experience to the table throughout this programme, proposing alternative works and solutions on many of the sites. For example, at the Mullagh Wastewater Treatment Plant upgrade, after our site review, we made design changes to use existing assets on site which removed the need to build a new additional storm tank. This saved CAPEX and OPEX costs considerably and freed up space for future upgrade works at the site. 

Similarly, for the storm tank cleaning systems aspect of the programme, initial site design had indicated a particular type of storm tank cleaning system, which required installation of a considerable washwater pumping station to be installed in order to feed the cleaning system with washwater for the process. 

Conway Engineering engaged with the market and sourced a different solution that needs no water to clean the tank. This resulted in a much reduced washwater pumping station requirement and corresponding decreased OPEX at the site, which delivered the best possible outcome for our client.